“Cannabis (marijuana) is one of the most consumed psychoactive substances in the world. The term marijuana is of Mexican origin. The primary cannabinoids that have been studied to date include cannabidiol and delta-9-tetrahydrocannabinol, which is responsible for most cannabis physical and psychotropic effects. Recently, the endocannabinoid system was discovered, which is made up of receptors, ligands and enzymes that are widely expressed in the brain and its periphery, where they act to maintain balance in several homeostatic processes. Exogenous cannabinoids or naturally-occurring phytocannabinoids interact with the endocannabinoid system. Marijuana must be processed in a laboratory to extract tetrahydrocannabinol and leave cannabidiol, which is the product that can be marketed. Some studies suggest cannabidiol has great potential for therapeutic use as an agent with antiepileptic, analgesic, anxiolytic, antipsychotic, anti-inflammatory and neuroprotective properties; however, the findings on cannabinoids efficacy and cannabis-based medications tolerability-safety for some conditions are inconsistent. More scientific evidence is required in order to generate recommendations on the use of medicinal cannabis.”
“The most recent studies published or initiated in the last 18 months, investigating cannabidiol in the treatment of symptoms of schizophrenia and related conditions are summarized, including observed tolerability and reported side-effects.
Recent studies focused on patients with sub-acute psychotic syndromes of schizophrenia, clinical high-risk state for psychosis (CHR-P), or frequent cannabis users, as well as cognitive functioning in chronic schizophrenia. There is further, although not consistent evidence for cannabidiol-reducing positive symptoms, but not negative symptoms. Evidence for improvement of cognition was weaker, with one study reporting a worsening. Regarding side effects and tolerability, cannabidiol induced sedation in one study, with the other studies indicating good tolerability, even at high doses.
Recent clinical trials added further evidence for an antipsychotic potential of cannabidiol. In general, studies following trial designs as suggested by regulators in schizophrenia are needed in sufficient numbers to clarify the safety and efficacy of cannabidiol herein. In addition, such studies will further elucidate its ability to target specific aspects of the syndrome, such as negative or cognitive symptoms. Furthermore, aiming for an add-on treatment with cannabidiol will require further studies to identify potentially useful or even harmful combinations.”
“Recent evidence suggests that cannabidiol (CBD), a non-intoxicating ingredient present in cannabis extract, has an antipsychotic effect in people with established psychosis. However, the effect of CBD on the neurocognitive mechanisms underlying psychosis is unknown.
Patients with established psychosis on standard antipsychotic treatment were studied on separate days at least one week apart, to investigate the effects of a single dose of orally administered CBD (600 mg) compared to a matched placebo (PLB), using a double-blind, randomized, PLB-controlled, repeated-measures, within-subject cross-over design. Three hours after taking the study drug participants were scanned using a block design functional magnetic resonance imaging (fMRI) paradigm, while performing a verbal paired associate learning task. Fifteen psychosis patients completed both study days, 13 completed both scanning sessions. Nineteen healthy controls (HC) were also scanned using the same fMRI paradigm under identical conditions, but without any drug administration. Effects of CBD on brain activation measured using the blood oxygen level-dependent hemodynamic response fMRI signal were studied in the mediotemporal, prefrontal, and striatal regions of interest.
Compared to HC, psychosis patients under PLB had altered prefrontal activation during verbal encoding, as well as altered mediotemporal and prefrontal activation and greater mediotemporal-striatal functional connectivity during verbal recall. CBD attenuated dysfunction in these regions such that activation under its influence was intermediate between the PLB condition and HC. CBD also attenuated hippocampal-striatal functional connectivity and caused trend-level symptom reduction in psychosis patients.
This suggests that normalization of mediotemporal and prefrontal dysfunction and mediotemporal-striatal functional connectivity may underlie the antipsychotic effects of CBD.”
“Stress is a risk factor for psychosis and treatments which mitigate its harmful effects are needed.
Cannabidiol (CBD) has antipsychotic and anxiolytic effects.
We investigated whether CBD would normalise the neuroendocrine and anxiety responses to stress in clinical high risk for psychosis (CHR) patients.
One-way analysis of variance (ANOVA) revealed a significant effect of group (HC, CHR-P, CHR-CBD (p = .005) on cortisol reactivity as well as a significant (p = .003) linear decrease. The change in cortisol associated with experimental stress exposure was greatest in HC controls and least in CHR-P patients, with CHR-CBD patients exhibiting an intermediate response. Planned contrasts revealed that the cortisol reactivity was significantly different in HC compared with CHR-P (p = .003), and in HC compared with CHR-CBD (p = .014), but was not different between CHR-P and CHR-CBD (p = .70). Across the participant groups (CHR-P, CHR-CBD and HC), changes in anxiety and experience of public speaking stress (all p’s < .02) were greatest in the CHR-P and least in the HC, with CHR-CBD participants demonstrating an intermediate level of change.
Our findings show that it is worthwhile to design further well powered studies which investigate whether CBD may be used to affect cortisol response in clinical high risk for psychosis patients and any effect this may have on symptoms.”
“Antipsychotic effects of CBD have been linked to its effects on levels of the endogenous cannabinoid anandamide (AEA) potentially by inhibiting its catalytic enzyme fatty acid amide hydrolase (FAAH). Recent preclinical work has also suggested that CBD may block the anxiogenic effects of chronic stress that was associated with a concomitant decrease in the expression of FAAH following CBD treatment. To the best of our knowledge, this is the first study to have investigated the effects of short-term treatment with CBD on experimentally induced stress in the context of psychosis risk. Notwithstanding its limitations, the present study provides a strong rationale for future studies to investigate whether CBD may have potential to mitigate the harmful effects of stress in the course of daily life by attenuating the altered neuroendocrine and psychological responses to acute stress in CHR participants.”
“Cannabidiol (CBD), a non-psychotropic cannabinoid, demonstrates antipsychotic-like and procognitive activities in humans and in animal models of schizophrenia.
The mechanisms of these beneficial effects of CBD are unknown. Here, we examined behavioral effects of CBD in a pharmacological model of schizophrenia-like cognitive deficits induced by repeated ketamine (KET) administration. In parallel, we assessed transcriptional changes behind CBD activities in the prefrontal cortex (PFC), the main brain area linked to schizophrenia-like pathologies.
Male Sprague-Dawley rats were injected for 10 days with KET followed by 6 days of CBD. The cognitive performance was evaluated in the novel object recognition test followed by PFC dissections for next-generation sequencing (RNA-Seq) analysis and bioinformatics.
We observed that KET-induced learning deficits were rescued by CBD (7.5 mg/kg).
Similarly, CBD reversed transcriptional changes induced by KET. The majority of the genes affected by KET and KET-CBD were allocated to astroglial and microglial cells and associated with immune-like processes mediating synaptogenesis and neuronal plasticity. These genes include C1qc, C1qa, C1qb, C2, and C3 complement cascade elements, Irf8 factor and Gpr84, Gpr34, Cx3cr1, P2ry12, and P2ry6 receptors. The main pathway regulators predicted to be involved included TGFβ1 and IFNγ. In addition, CBD itself upregulated oxytocin mRNA in the PFC.
The present data suggest that KET induces cognitive deficits and transcriptional changes in the PFC and that both effects are sensitive to a reversal by CBD treatment.”
“Accumulating evidence implicates the endocannabinoid system in the pathophysiology of psychosis.
If the endocannabinoid system plays a role in psychosis pathophysiology, it raises the interesting possibility that pharmacological compounds that modulate this system may have therapeutic value.
Cannabidiol (CBD), a phytocannabinoid constituent of Cannabis sativa, has been heralded as one such potential treatment.
Cannabidiol (CBD), a non-intoxicating constituent of the cannabis plant, has emerged as a potential novel class of antipsychotic with a unique mechanism of action.
In this review, we set out the prospects of CBD as a potential novel treatment for psychotic disorders.
In sum, CBD currently represents a promising potential novel treatment for patients with psychosis.”
“Accumulating evidence points towards the antipsychotic potential of cannabidiol. However, the neurocognitive mechanisms underlying the antipsychotic effect of cannabidiol remain unclear.
We investigated this in a double-blind, placebo-controlled, parallel-arm study. We investigated 33 antipsychotic-naïve subjects at clinical high risk for psychosis (CHR) randomised to 600 mg oral cannabidiol or placebo and compared them with 19 healthy controls.
We used the monetary incentive delay task while participants underwent fMRI to study reward processing, known to be abnormal in psychosis. Reward and loss anticipation phases were combined to examine a motivational salience condition and compared with neutral condition.
We observed abnormal activation in the left insula/parietal operculum in CHR participants given placebo compared to healthy controls associated with premature action initiation. Insular activation correlated with both positive psychotic symptoms and salience perception, as indexed by difference in reaction time between salient and neutral stimuli conditions.
CBD attenuated the increased activation in the left insula/parietal operculum and was associated with overall slowing of reaction time, suggesting a possible mechanism for its putative antipsychotic effect by normalising motivational salience and moderating motor response.”
“The endogenous cannabinoid (eCB) system plays an important role in the pathophysiology of both psychotic disorders and substance use disorders (SUDs). The non-psychoactive cannabinoid compound, cannabidiol (CBD) is a highly promising tool in the treatment of both disorders. Here we review human clinical studies that investigated the efficacy of CBD treatment for schizophrenia, substance use disorders, and their comorbidity. In particular, we examined possible profiles of patients who may benefit the most from CBD treatment. CBD, either as monotherapy or added to regular antipsychotic medication, improved symptoms in patients with schizophrenia, with particularly promising effects in the early stages of illness. A potential biomarker is the level of anandamide in blood. CBD and THC mixtures showed positive effects in reducing short-term withdrawal and craving in cannabis use disorders. Studies on schizophrenia and comorbid substance use are lacking. Future studies should focus on the effects of CBD on psychotic disorders in different stages of illness, together with the effects on comorbid substance use. These studies should use standardized measures to assess cannabis use. In addition, future efforts should be taken to study the relationship between the eCB system, GABA/glutamate, and the immune system to reveal the underlying neurobiology of the effects of CBD.”
“Cognitive impairment is a major source of disability in schizophrenia and current antipsychotic drugs (APDs) have minimal efficacy for this symptom domain.
Cannabidiol (CBD), the major non-intoxicating component of Cannabis sativa L., exhibits antipsychotic and neuroprotective properties.
We recently reported the effects of CBD on cognition in male offspring of a maternal immune activation (polyinosinic-polycytidilic acid (poly I:C)) model relevant to the aetiology of schizophrenia; however, the effects of CBD treatment in females are unknown. Sex differences are observed in the onset of schizophrenia symptoms and response to APD treatment.
Furthermore, the endogenous cannabinoid system, a direct target of CBD, is sexually dimorphic in humans and rodents. Therefore, the present work aimed to assess the therapeutic impact of CBD treatment on behaviour and neurochemical signalling markers in female poly I:C offspring.
Overall, the findings of this study support the therapeutic benefits of CBD on recognition memory and sociability in female poly I:C offspring, and provide insight into the neurochemical changes that may underlie the therapeutic benefits of CBD in the poly I:C model.”
“These findings suggest that CBD is an efficacious treatment for behavioural and neurochemical changes in a female rodent model relevant to schizophrenia.”
“The present findings reveal an imbalance in the expression and function of different elements of the endocannabinoid system in schizophrenia.
This outcome highlights the relevance of the endocannabinoid system in the pathophysiology of schizophrenia and emphasises its elements as potential targets in the search for new therapeutic strategies.”
“Therapeutic potential of cannabinoids in schizophrenia.” https://www.ncbi.nlm.nih.gov/pubmed/24605939
“Cannabinoids for the Treatment of Schizophrenia: An Overview. Cannabinoids are found to be very useful in psychiatry because of their antipsychotic properties suggesting a therapeutic use. Cannabinoids treatments are both able to reduce the typical symptoms of schizophrenia and to slow down the disease aggravation.” https://www.ncbi.nlm.nih.gov/pubmed/26845552